(1) Field of the Invention
The present invention relates to lights and, more particularly, warning lights having a wide angle radiation pattern, particularly in a single plane. Accordingly, the general objects of the present invention are to provide novel and improved devices of such character.
(2) Description of the Prior Art
Warning light systems which are employed on emergency vehicles, such as police cars, ambulances, fire trucks and the like, are often required to emit bursts of light which are readily visible from all sides of the vehicle. The warning lights of such systems may comprise a revolving incandescent lamp assembly, a moving mirror and cooperating lamp or a flash tube and cooperating lens and reflector. The prior art warning lights can be relatively expensive to manufacture. Additional drawbacks of many prior art warning lights is poor volumetric efficiency and high wind resistance.
A number of improved lights having particular applicability to emergency vehicle warning light systems have recently been introduced. Many such lights employ xenon flash tubes and have found wide popularity. For example, U.S. Pat. No. 4,792,717, which is assigned to the assignee of the present invention, discloses a compact wide-angle warning light. This warning light employs a concave reflector, a lens and a light emitter in the form of a specially designed xenon flash tube. The reflector comprises a linear section having parabolic side walls which are disposed between parabolic dish end sections.
In co-pending application Ser. No. 312,479 now U.S. Pat. No. 4,954,958, which is also assigned to the assignee of the present invention, a lamp assembly comprising a single light emitter, a reflector body and a lens cover which mounts over the reflector body is disclosed. The reflector body comprises a first parabolic dish-like reflector surface which forms a surface of revolution about a central axis. A mounting base projects from the first reflector surface for mounting a light emitter such as a halogen lamp or a gaseous discharge tube. The central axis extends through the emitter mounting base. A pair of reflector wings are located at equidistantly-spaced diametral positions from the central axis. The wings each define a parabolic reflector surface which has its axis canted in relation to the first reflector surface, i.e., the surfaces from which light is reflected are defined by three parabolas and these three parabolas have, to the extent manufacturing tolerances permit, a common focal point. The lens cover preferably includes a multiplicity of light spreaders which project interiorly from the cover surface. A pair of recesses are formed in the cover interior for mating with the outwardly disposed shoulder portions of the wings so as to mount the lens to the reflector body and to angularly fix the orientation of the axes of the spreaders relative to the reflector body. A source of radiation, optionally in the form of a halogen lamp or a gas discharge tube, is positioned in the envelope between the lens cover and the reflector body at the common focal point of the reflector defined parabolas and produces a generally uni-directional, wide angle beam pattern which radiates through the lens.